Spring coils for innerspring assemblies and methods of manufacture

Abstract

A progressive spring coil comprises a first spring portion comprising a top end and a bottom end and having a first spring rate, wherein the first spring rate is substantially linear or substantially nonlinear; a second spring portion comprising a top end and a bottom end and having a second spring rate, wherein the second spring rate is substantially linear or substantially nonlinear; and a third spring portion disposed between the first spring portion and the second spring portion, wherein the third spring portion has a third spring rate, wherein the third spring rate is substantially linear or substantially nonlinear.

What is claimed is: 
     
       1. A progressive spring coil, comprising:
 a first spring portion having a substantially conical shape defined by a plurality of convolutions having a first pitch, the first spring portion comprising a top end and a bottom end and having a first spring rate, wherein the first spring rate is substantially linear or substantially nonlinear, and wherein the top end has a diameter less than a diameter of the bottom end; 
 a second spring portion having a substantially conical shape defined by a plurality of convolutions having a second pitch, the second spring portion comprising a top end and a bottom end and having a second spring rate, wherein the second spring rate is substantially linear or substantially nonlinear, and wherein the top end has a diameter larger than a diameter of the bottom end; and 
 a third spring portion having a substantially cylindrical or a substantially hyperbolic shape disposed between the first spring portion and the second spring portion and defined by a plurality of convolutions having a third pitch, wherein the third spring portion has a third spring rate, and wherein the third spring rate is substantially linear or substantially nonlinear, 
 wherein the first pitch of the first spring portion is less than the second pitch of the second spring portion and less than the third pitch of the third spring portion, and wherein the third spring portion further comprises a first transition loop disposed between the bottom end of the first spring portion and the third spring portion and a second transition loop disposed between the to end of the second spring portion and the third spring portion, wherein a pitch of the second transition loop is greater than the pitch of the first transition loop. 
 
     
     
       2. The progressive spring coil of  claim 1 , wherein the first spring portion is disposed above the second spring portion. 
     
     
       3. The progressive spring coil of  claim 1 , wherein the third spring portion is substantially cylindrical. 
     
     
       4. The progressive spring coil of  claim 1 , wherein the third spring portion is substantially hyperbolic. 
     
     
       5. The progressive spring coil of  claim 1 , wherein the third spring rate is greater than the first and the second spring rates. 
     
     
       6. The progressive spring coil of  claim 1 , wherein the second spring rate is greater than the first spring rate and is lower than the third spring rate. 
     
     
       7. The progressive spring coil of  claim 1 , wherein the first spring portion is configured to substantially fully compress before the third spring portion and the second spring portion substantially compress. 
     
     
       8. The progressive spring coil of  claim 1 , wherein the first pitch of the first spring portion is between about 0.5 centimeters and about 1.5 centimeters or about 1.5% and 7.5% of a total height of the spring coil. 
     
     
       9. The progressive spring coil of  claim 8 , wherein the third pitch of the third spring portion is between about 3 centimeters and about 5 centimeters or about 10% and 25% of the total spring coil height. 
     
     
       10. The progressive spring coil of  claim 1 , wherein a diameter of the first and the second transition loops is greater than a diameter of a plurality of substantially cylindrical convolutions of the third spring portion. 
     
     
       11. The progressive spring coil of  claim 10 , wherein the diameter of the plurality of substantially cylindrical convolutions of the third spring portion is less than a diameter of a lowest convolution of the bottom end of the first spring portion and less than a diameter of a highest convolution of the top end of the second spring portion. 
     
     
       12. The progressive spring coil of  claim 1 , wherein a pitch of the first transition loop is greater than the first pitch, the second pitch and the third pitch. 
     
     
       13. The progressive spring coil of  claim 1 , wherein the first spring portion, the second spring portion and the third spring portion are formed from a multi-stranded wire. 
     
     
       14. An innerspring assembly for cushioning an article, comprising:
 at least one asymmetric progressive spring coil configured to provide a three-phased load deflection response curve, wherein the progressive spring coils comprise:
 a first spring portion having a substantially conical shape defined by a plurality of convolutions having a first pitch and having a first substantially linear spring rate or a first substantially nonlinear spring rate; 
 a second spring portion having a substantially conical shape defined by a plurality of convolutions having a second pitch and having a second substantially linear spring rate or a second substantially nonlinear spring rate; and 
 a third spring portion having a substantially cylindrical or a substantially hyperbolic shape disposed between the first spring portion and the second spring portion, wherein the third spring portion is defined by a plurality of convolutions having a third pitch and has a third substantially linear spring rate or a third substantially non-linear spring rate, 
 
 wherein the first pitch of the first spring portion is less than the second pitch of the second spring portion and less than the third pitch of the third spring portion, and wherein the third spring portion further comprises a first transition loop disposed between the bottom end of the first spring portion and the third spring portion and a second transition loop disposed between the top end of the second spring portion and the third spring portion, wherein a pitch of the second transition loop is greater than the pitch of the first transition loop. 
 
     
     
       15. The innerspring assembly of  claim 14 , wherein the first spring portion, the second spring portion and the third spring portion are formed form a multi-stranded wire having a uniform diameter. 
     
     
       16. A method of manufacturing a cushioned article, comprising
 providing a plurality of asymmetric progressive spring coils, wherein each spring coil of the plurality comprises a first spring portion having a substantially conical shape defined by a plurality of convolutions having a first pitch and having a first substantially linear spring rate or a first substantially nonlinear spring rate; a second spring portion having a substantially conical shape defined by a plurality of convolutions having a second pitch and having a second substantially linear spring rate or a second substantially nonlinear spring rate; and a third spring portion disposed between the first spring portion and the second spring portion, wherein the third spring portion having a substantially cylindrical or a substantially hyperbolic shape defined by a plurality of convolutions having a third pitch and has a third substantially linear spring rate or a third substantially nonlinear spring rate, wherein the first pitch of the first spring portion is less than the second pitch of the second spring portion and less than the third pitch of the third spring portion, and wherein each progressive spring coil is configured to provide a three-phased load deflection response curve, and wherein the third spring portion further comprises a first transition loop disposed between the bottom end of the first spring portion and the third spring portion and a second transition loop disposed between the top end of the second spring portion and the third spring portion, wherein a pitch of the second transition loop is greater than the pitch of the first transition loop; 
 connecting each progressive spring coil to an adjacent progressive spring coil to form one or more rows; 
 arranging the one or more rows of the plurality of asymmetric progressive spring coils form an innerspring assembly; and 
 disposing at least one additional layer in physical communication with the inner spring assembly.